Switchable lamp shade or covering

ABSTRACT

A lamp shade or cover that can be readily switched from a translucent-opaque mode to a transparent mode if the shade or cover from a material with transparency properties that can be modulated. A layer of liquid crystals encapsulated between transparent electrodes is included in the shade. Normally, the liquid crystals are randomly oriented and diffuse light so as to create a translucent state. When a direct current voltage is applied across the transparent electrodes, the liquid crystals become oriented and essentially transparent. Application of a pulsed or alternating current voltage can be used to modulate the degree of transparency.

CROSS-REFERENCE TO PRIOR APPLICATIONS

This application is based on and claims benefit and priority from U.S.Provisional Patent Application No. 62/878,551 filed on 25 Jul. 2019.

U.S. GOVERNMENT SUPPORT

Not applicable.

BACKGROUND OF THE INVENTION Area of the Art

The present invention relates to lighting and more specifically to animproved lamp shade or cover.

DESCRIPTION OF THE BACKGROUND OF THE INVENTION

Lamp shades and lamp covers have a number of decorative and functionalproperties. By “lamp shade” I mean a separate structure that covers alight source such as a light bulb. Depending on the properties of thelamp shade material, a lamp shade's purpose may be primarily to diffuseand/or reflect the light rays from the light source. For example, a lampshade may be constructed of a totally opaque (a material that lightcannot pass through) material that has a white or reflective innersurface and (usually) a colored and/or textured outer surface. In thatcase the outer surface usually performs a decorative purpose and iscolor with or covered with fabric that is harmonious with thesurrounding furniture. When the light source is turned on, the innersurface of the lamp shade redirects the light in a downward direction asto on a desk or table for reading purposes. It is more common that thelamp shade material not be totally opaque so that a small amount oflight passes through the shade when the light source is operational. Inthis way the fabric or color that covers the shade is illuminated by thelight source which produces a decorative effect while the shade blocksthe glare of gazing directly at the light source. A “lamp cover”performs the same function but is usually considered to entirely envelopthe light source without leaving a direct pat for the light rays as inthe case of a light shade.

It would be desirable to produce lamp shades or covers that were capableof altering their transparency to the amount of light passing throughthe shade or cover could be modulated. When the shade or cover is fullytransparent the light source can be seen clearly unless the shade iscovered by fabric or a similar material. Seeing the source directly andwithout significant attenuation is advantageous where it is desired tomaximally illuminate the surroundings and/or display a decorative aspectof the light source—for example a decorative “Edison-type” filament.With a fabric cover additional light will illuminate the fabric for adecorative effect. When the shade or cover is set to be opaque, less oreven no light passes through and a greater amount of light is reflectedfrom the inner surface of the shade.

SUMMARY OF THE INVENTION

A lamp shade or cover that can be readily switched from atranslucent-opaque mode to a transparent mode is achieved byconstructing the shade or cover from a material with transparencyproperties that can be modulated. Perhaps the simplest material havingsuch properties includes a layer of liquid crystals encapsulated betweentransparent electrodes. In its native state the liquid crystals arerandomly oriented and diffuse light so as to create a translucent state.If the layer of liquid crystals is made sufficiently thick, it willbecome essentially opaque. Then a direct current voltage is appliedacross the transparent electrodes, the liquid crystals become orientedand essentially transparent. Application of a pulsed or alternatingcurrent voltage can be used to modulate the degree of transparency.Alternatively, if the electrodes and the liquid crystals sandwichedthere between are placed between crossed polarizing films, the coverwill be opaque until a voltage is applied to the electrodes causing theliquid crystals to orient which rotates the polarization plane of lightallowing light to pass through the crossed polarizing films. Othermethods of modulating transparency include pumping or blowing particlesor liquids between spaced apart transparent layers.

DESCRIPTION OF THE FIGURES

The application file contains at least one drawing executed in color.Copies of this patent or patent application publication with colordrawing(s) will be provided by the Office upon request and payment ofthe necessary fee.

FIG. 1 shows a globe-shaped lamp cover being switched from a fullytransparent mode (FIG. 1a ) to a translucent mode (FIG. 1b ); and

FIG. 2 shows a lamp shade being switched from a fully transparent mode(FIG. 2a ) to a translucent mode (FIG. 2b ).

DETAILED DESCRIPTION OF THE INVENTION

The following description is provided to enable any person skilled inthe art to make and use the invention and sets forth the best modescontemplated by the inventor of carrying out his invention. Variousmodifications, however, will remain readily apparent to those skilled inthe art, since the general principles of the present invention have beendefined herein specifically to provide lamp shades or lamp covers havinga switchable or adjustable optical profile—that is, a shade capable ofaltering its degree of transparency.

The technology behind how transparency of the shade/cover is altered isnot germane to the present invention. One way of rapidly adjusting thetransparency of a shade or cover is to apply or embed a specializedliquid crystal layer to the shade cover. Such a method operatessimilarly to liquid crystals in the currently ubiquitous Liquid CrystalDisplay (LCD). In a liquid crystal film intended for transparencymodulation, the liquid crystals are encapsulated between transparentelectrodes. In its normal state, the liquid crystals present a milkyappearance and strongly diffuse light passing through. If the layer ofliquid crystals is made sufficiently thick, virtually no light will passthrough. When a direct current voltage is present on the transparentelectrodes, the liquid crystals become oriented by the electric field.In their oriented state, the liquid crystals do not scatter or otherwiseinteract with light to a significant degree and the film becomes fullytransparent. Because the liquid crystals take a finite amount of time toreorient, rapidly pulsing the electric field can be used to adjust thefilm from full transparency (field on 100% of the time), to translucency(pulsed field with a 25% duty cycle) to fully opaque (no electricfield).

FIG. 1 shows a lamp cover (a globe surrounding a light source) beingswitched from a fully transparent mode (FIG. 1a ) to atranslucent/opaque mode (FIG. 1b ). When the cover is transparent, thelight source can be clearly seen, and light from the source reaches agreater distance. When in the translucent/opaque mode the light isdiffused and while not reaching as far (translucent mode), providesbetter local illumination (translucent mode) because sharp shadows arenot cast.

FIG. 2 shows a conventional lamp shade being switched from a fullytransparent mode (FIG. 2a ) to a translucent/opaque mode (FIG. 2b ).When the shade is transparent, the light source can be clearly seen andlight from the source reaches a greater distance. When in thetranslucent/opaque mode the light is diffused and while not reaching asfar, provides better local illumination (translucent mode)—particularlysince the light is reflected and directed mostly in a downwarddirection.

The following claims are thus to be understood to include what isspecifically illustrated and described above, what is conceptuallyequivalent, what can be obviously substituted and also what essentiallyincorporates the essential idea of the invention. Those skilled in theart will appreciate that various adaptations and modifications of thejust-described preferred embodiment can be configured without departingfrom the scope of the invention. The illustrated embodiment has been setforth only for the purposes of example and that should not be taken aslimiting the invention. Therefore, it is to be understood that, withinthe scope of the appended claims, the invention may be practiced otherthan as specifically described herein.

What is claimed is:
 1. A lamp shade or lamp cover for covering orenclosing a light source comprising a material that can be switched froma transparent mode to a translucent mode, wherein when the lamp shade orlamp cover is in the transparent mode, the light source can be seenthrough the lamp shade or lamp cover and wherein the lamp shade or lampcover is in the translucent-mode, the light source is diffused.
 2. Thelamp shade or lamp cover of claim 1, wherein the material includesencapsulated liquid crystals and transparent electrodes.
 3. The lampshade or lamp cover of claim 2, wherein a voltage is applied to thetransparent electrodes to switch the material from the translucent-modeto the transparent mode.